1. Technical Field
The present invention relates to a dual anchor assembly for embedment in concrete slabs and to a lifting shackle adapted to simultaneously engage the multiple anchors of the assembly. In its more particular aspects, the invention is concerned with a void former which provides for positioning and placement of the anchors and forms an arcuate recess in the slab in intersecting relationship with the anchors. It is also concerned with an anchor assembly and hoisting shackle of increased load capacity, as compared to existing assemblies and shackles which employ single anchors.
2. Description of the Prior Art
The prior art relating to the present invention is typified by U.S. Pat. Nos. 3,883,170 and 4,367,892. These patents show single anchor assemblies for embedment in concrete slabs and associated releasable lifting shackles for engagement with the anchors. They also teach the provision of an arcuate recess around the end of the anchor engaged by the shackle. The '892 patent, in particular, teaches a void former for forming the recess and placing the anchor.
It is also known in the prior art to provide anchor assemblies for embedment in concrete slabs, wherein the anchors have divergent portions to spread the load and resist pullout. Such a device, for use with a releasable lifting shackle, may be since in U.S. Pat. No. 4,173,856. In the device of that patent, however, each shackle engages only a single anchor.